Lens driving module with casing having plastic material and assembly method thereof

ABSTRACT

An optical element driving module is provided, including: a casing; a base, including at least one protrusion extending toward the casing, and the protrusion has a side surface, wherein the casing is fixed on the base; a holder for holding an optical element having an optical axis; a driving assembly disposed in the casing for moving the holder relative to the casing and the base; and a plurality of gluing elements disposed between the side surface and the casing, wherein the side surface is parallel to the optical axis.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of application Ser. No. 15/880,013,filed on Jan. 25, 2018, which claims priority of Taiwan PatentApplication No. 106102855, filed on Jan. 25, 2017, the entirety of whichis incorporated by reference herein.

BACKGROUND OF THE INVENTION Field of the Invention

The application relates in general to a lens driving module and theassembly method thereof, and in particular to a lens driving moduleincluding a base having a plurality of protrusions.

Description of the Related Art

Thanks to ongoing technological developments, recent electronic devices(such as tablet computers and smartphones) usually include a lens modulecapable of aiding in photography or recording video. In the process ofassembling the lens module, there is a sub-process for assembling thecasing and affixing it to the base of the lens driving module. However,since a tolerance exists when components are manufactured, when thecasing is assembled or attached to the surface of the base, the contactsurface between them can become tilted or skewed, which will negativelyimpact the proper operation of the lens module. In addition, the openingof the casing usually requires additional space for a tool to apply glueto the components in the casing for the purpose of connecting them, butthis tends to allow external dust and particles to enter the lens unitduring the assembly process, thereby leading to damage of the lensmodule.

BRIEF SUMMARY OF INVENTION

To address the deficiencies of conventional products, an embodiment ofthe invention provides a lens driving module configured to drive anoptical lens, including a holder, a casing, a base, an electromagneticdriving assembly and a glue. The optical lens is disposed in a receivingspace of the holder. The holder is disposed between the casing and thebase. The casing has a plastic material. The electromagnetic drivingassembly is disposed between the holder and the casing for moving theholder. The base has a plurality of protrusions extending toward thecasing, and each of the protrusions has a side surface. The glue isdisposed between the side surfaces and the casing, wherein the sidesurface is parallel to the central axis of the optical lens.

In some embodiments, the side surfaces of the protrusions respectivelyhave a first surface and a second surface that are perpendicular to eachother and an angled surface that is angled relative to the first andsecond surfaces, wherein a gap is formed between the casing and thefirst, second, and angled surfaces.

In some embodiments, the lens driving module further comprises a firstelastic element and a second elastic element, and the base further has amain body from which the protrusions protrude, wherein the first elasticelement connects the holder to the main body, and the second elasticelement connects the protrusions to the holder.

In some embodiments, the base has a rectangular structure, and thesecond elastic element has a cross section, wherein the cross sectionpasses through the central axis and is parallel to a side of therectangular structure, and the cross section only includes one sectionof the second elastic element on the opposite side of the central axis.

In some embodiments, the holder has a connecting surface connecting thesecond elastic element, and the connecting surface and the casing atleast partially overlap in the direction of the central axis.

In some embodiments, the casing has a plurality of grooves which areformed on an inner surface of the casing and which are configured toreceive the glue.

In some embodiments, the electromagnetic driving assembly includes atleast one magnetic element disposed on an inner side of the casing, andthe protrusions are situated in the casing.

In some embodiments, each protrusion has a positioning bump. The secondelastic element has a plurality of locating holes, and the positioningbumps are correspondingly incorporated within the locating holes.

An embodiment of the invention provides a method for assembling a lensdriving module, including assembling a holder on a first elasticelement, wherein the holder is configured to hold an optical lens;assembling the holder and the first elastic element on a base;assembling a second elastic element on a plurality of protrusions of thebase; applying a glue to the inner surface of a casing; and disposingthe casing around the base, wherein the glue flows to side surfaces ofthe protrusions from the inner surface, and the side surfaces areparallel to the central axis of the optical lens.

In some embodiments, the method for assembling the lens module furtherincludes attaching the second elastic element to the protrusions and theholder before disposing the casing around the base.

In some embodiments, the inner surface has a plurality of grooves, andthe glue is applied between the grooves and a sidewall of the casing.

Another embodiment of the invention provides a lens driving moduleconfigured to drive an optical lens, including a holder, a casing, abase, an electromagnetic driving assembly, a glue, and a sensingassembly. The optical lens is disposed in a receiving space of theholder. The casing has a plastic material. The holder is disposedbetween the casing and the base. The base has a plurality of protrusionsextending toward the casing, and each of the protrusions has a sidesurface. The electromagnetic driving assembly is disposed between theholder and the casing for forcing the holder and the optical lens tomove relative to the base. The glue is disposed between the sidesurfaces and the casing, wherein the side surface is parallel to thecentral axis of the optical lens. The sensing assembly is disposed onthe casing and configured to sense the relative position of the holderand the base.

In some embodiments, the sensing assembly is formed on the inner wall ofthe casing by insert Molding or 3D molded interconnect devicetechnology.

In some embodiments, the casing defines a main body and a firstsub-sidewall, the first sub-sidewall is detachably connected to the mainbody, and the sensing assembly is disposed on the first sub-sidewall.

In some embodiments, there is a slit between the casing and the basewhen the casing is assembled on the base, and the sensing assembly isable to pass through the slit to connect with the casing.

In some embodiments, the casing has a holding portion, the holdingportion and the sidewall of the casing define a receiving recessconfigured to receive the sensing assembly.

In some embodiments, a cross section of the receiving recess forms aU-shaped structure.

Another embodiment of the invention provides a lens driving moduleconfigured to drive a plurality optical lenses, including a firstholder, a second holder, a casing, a base, an electromagnetic drivingassembly and a sensing assembly. The first and the second holders areconfigured to sustain a first optical lens and a second optical lens,respectively. The casing has a plastic material. The base is connectedto the casing, wherein a receiving space is defined by the casing andthe base, and the first and second holders are disposed in the receivingspace. The electromagnetic driving assembly is disposed in the receivingspace and configured to force the first and second holders to moverelative to the base. The sensing assembly is disposed on the casing andconfigured to sense the relative position of the first and secondholders and the base.

In some embodiments, the lens driving module further comprises apermeability element disposed between the casing and the first andsecond holders and configured to correspond to the electromagneticdriving assembly.

BRIEF DESCRIPTION OF DRAWINGS

The invention can be more fully understood by reading the subsequentdetailed description and examples with references made to theaccompanying drawings, wherein:

FIG. 1 is a schematic diagram of a lens driving module according to anembodiment of the invention.

FIG. 2A is an exploded view of the lens driving module in FIG. 1.

FIG. 2B is another exploded view of the lens driving module in FIG. 1.

FIG. 3A is a sectional view diagram taken along line A-A′ in FIG. 1.

FIG. 3B is a sectional view diagram taken along line C-C′ in FIG. 1.

FIG. 4A is a schematic diagram of the base, holder and the secondelastic element in FIGS. 2A-2B.

FIG. 4B is a sectional view diagram taken along line B-B′ in FIG. 4A(the holder 20 is omitted).

FIG. 5 is a schematic diagram of the casing in FIGS. 2A-2B.

FIGS. 6A to 6E are schematic diagrams of assembly of the lens drivingmodule.

FIG. 7 is a flowchart of a method for assembling a lens driving moduleaccording to an embodiment of the invention.

FIGS. 8A and 8B are schematic diagrams of a lens driving moduleaccording to another embodiment of the invention.

FIG. 8C is a schematic diagram of the configuration of the casing andthe sensing assembly.

FIG. 8D is a sectional view diagram taken along line D-D′ in FIG. 8C.

FIG. 9 is a schematic diagram of a lens driving module according toanother embodiment of the invention.

FIG. 10 is a schematic diagram of a lens driving module according toanother embodiment of the invention.

FIG. 11 is a schematic diagram of a lens driving module comprising apermeability element according to another embodiment of the invention.

DETAILED DESCRIPTION OF INVENTION

The making and using of the embodiments of the lens driving modules arediscussed in detail below. It should be appreciated, however, that theembodiments provide many applicable inventive concepts that can beembodied in a wide variety of specific contexts. The specificembodiments discussed are merely illustrative of specific ways to makeand use the embodiments, and do not limit the scope of the disclosure.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood to one of ordinary skill inthe art to which this invention belongs. It should be appreciated thateach term, which is defined in a commonly used dictionary, should beinterpreted as having a meaning conforming to the relative skills andthe background or the context of the present disclosure, and should notbe interpreted in an idealized or overly formal manner unless definedotherwise.

Embodiment 1

FIG. 1 is a schematic diagram of a lens driving module 1 according to anembodiment of the invention, and FIGS. 2A and 2B are exploded viewdiagrams of the lens driving module 1. The lens driving module 1 can bedisposed in an electronic device, such as a camera, a tablet computer,or a cell phone, and it can be configured with an optical lens (notshown) therein. The lens driving module 1 can force the optical lens tomove relative to an image sensor disposed in the electronic device, sothat the focal length of the optical lens can be adjusted, to achievethe function of auto-focusing (AF).

As shown in FIGS. 1, 2A, and 2B, the lens driving module 1 primarilycomprises a base 10, a holder 20, a casing 30 (having a plasticmaterial, wherein the plastic material may contain substances such asceramics, fibers or metals as a filler), a first elastic element 40, asecond elastic element 50, a plurality of coils C, and a plurality ofmagnetic elements (such as magnets) M. The holder 20 has a receivingspace 21 and an optical lens (not shown) can be disposed therein. Anelectromagnetic assembly is consist of the coils C and the magneticelements M, configured to force the holder 20 and the optical lens tomove relative to the base 10. The coils C are disposed on the sides ofthe holder 20 and have an elliptical structure respectively. Themagnetic elements M are respectively disposed in a recess 31 of thecasing 30 and face the coils C, wherein the recesses 31 are formed onthe inner side of the casing 30. In some embodiments, the coils C mayelectronically connect to an external circuit to receive electriccurrent via the first elastic element 40 and electronic pins (notshown), so that a magnetic force is provided between the coils C and themagnetic elements M to force the holder 20 to move with respect to thebase 10 along a central axis O of the optical lens (Z-axis).

Referring to FIGS. 2A and 3A, FIG. 3A is sectional view diagram of thelens driving module 1 taken along line A-A′ in FIG. 1. The holder 20 isdisposed between the base 10 and the casing 30, wherein the base 10includes a main body 11 and plurality of protrusions 12. The main body11 has a substantially rectangular structure and an opening 111 extendsthrough the main body 11. The opening 111 is aligned with the centralaxis O of the optical lens, and the four protrusions 12 are arranged infour corners of the main body 11 and protrude from the main body 11toward the casing 30. The first elastic element 40 is disposed on themain body 11 of the base 10 and connects the lower surface of the holder20 and the main body 11. The second elastic element 50 is disposed onthe protrusions 12 of the base 10 and the holder 20 and connects theprotrusions 12 to the upper surface of the holder 20. The holder 20 isdisposed between the first and second elastic elements 40 and 50. In anembodiment, the first and second elastic elements 40 and 50 are leafsprings having metal material. It should be understood that theelectromagnetic drive assembly consisting of the coils C and themagnetic elements M may be disposed between the holder 20 and the casing30, configured to force the holder 20 and the optical lens relative tothe base 10 to move.

Please refer to FIG. 4A, which is a schematic diagram of the secondelastic element 50, the holder 20, and the base 10. The second elasticelements 50 include a plurality of fixing portions 51, a connectingportion 52 with a substantial circle structure (from top view), and aplurality of arms L. The fixing portions 51 connect the connectingportion 52 via the arms L. When the second elastic element 50 isdisposed on the holder 20 and the base 10, a locating hole 511 of eachfixing portion 51 is correspondingly bonded to a positioning bump 121 ofeach protrusion 12 of the base 10, so that the second elastic element 50is steady assembled to the base 10, and the connecting portion 52 of thesecond elastic element 50 connects a connecting surface 22 of the holder20. The method of connection, for example, may be engagement or adhesivebonding. The connecting surface 22 is substantially circular from thetop view.

As shown in FIG. 4B, which is a sectional view diagram taken along lineB-B′ in FIG. 4A (the holder 20 is omitted), line B-B′ passes through thecentral axis O and is parallel to the lateral side of the main body 11.It can be seen from FIGS. 4A and 4B that only two sections 53 and 54(indicated by cross hatching lines) of the connecting portion 52 of thesecond elastic element 50 are cut by the cross section (line B-B′) ofthe second elastic element 50 on the opposite sides of central axis O.In other words, each of the four sides of the second elastic element 50in the present embodiment is formed with only a single layer of anelastic arm. Therefore, when the lens driving module 1 forces theoptical lens to move, the degree of deformation of the second elasticelement 50 can be reduced, so that the space occupied by the secondelastic element 50 may be decreased in the lens driving module 1.

Continuing with reference to FIG. 4A, the side surfaces 12R of eachprotrusion 12 of the base 10 includes a first surface 12-1, a secondsurface 12-2, and an angled surface 12-3. The first surface 12-1 and thesecond surface 12-2 are perpendicular to each other, and the angledsurface 12-3 is angled with respect to the first surface 12-1 and thesecond surface 12-2. When the casing 30 is assembled to the base 10, agap G is formed between the side surfaces 12R (including the firstsurface 12-1, the second surface 12-2, and the angled surface 12-3) andthe sidewall 30R of the casing 30, wherein a glue (or a viscose) (e.g.,a glue having a resin) may be applied to the gap G so that the casing 30can be attached securely to the base 10.

FIG. 5 is a schematic diagram of the casing 30. The casing 30 has asubstantially rectangular structure in which an opening 301 passesthrough and is aligned with the central axis O of the optical lens (FIG.2A). The casing 30 has an inner surface 32 surrounded by and thesidewall 30R, wherein a plurality of grooves 32G are formed on the innersurface 32 and respectively adjacent to the four corners of the innersurface 32. The grooves 32G have arcuate structures. In addition, asector-shaped corner area N is formed between the sidewall 30R and thegroove 32G, and the glue may be placed or applied thereto. When thecasing 30 is assembled to the base 10, as shown in the cross-sectionalview of FIG. 3 taken along line C-C′ in FIG. 1, the glue flows from thecorner area N along the guide surface S (angled with respect to theinner surface 32) into the gap G between the casing 30 and the base 10,and then it flows to the side surface 12R of the protrusion 12 of thebase 10. Therefore, the first surface 12-1, the second surface 12-2, andthe angled surface 12-3 of the protrusion 12 are effectively connectedto the sidewall 30R by the glue, so that the casing 30 and the base 10are securely assembled. As a result, the entire structural strength ofthe lens driving module 1 can be enhanced by the surfaces 12-1, 12-2,and 12-3 as the bonding surfaces of the casing 30 and the base 10.Moreover, since the inner surface 32 of the casing 30 is provided with agroove 32G which can be used to contain and restrict the glue fromoverflowing, when the glue is applied to the corner area N or during theassembly of the casing 30 and the base 10, it is possible to prevent theglue from flowing toward the center of the inner surface 32 or thecenter of the opening 111 of the base 10, thereby effectively preventingdamage to the optical lens.

The assembly method of the lens driving module 1 is described withreference to FIGS. 6A to 6E. First, as shown in FIG. 6A, the coils C areassembled to the holder 20, and the holder 20 is disposed on the firstelastic element 40, wherein the holder 20 is connected with a portion ofthe first elastic element 40. The connection method, for example, may beengagement or adhering. Next, as shown in FIG. 6B, the holder 20 and thefirst elastic element 40 are assembled to the base 10, wherein a portionof the first elastic element 40 is connected to the main body 11 of thebase 10. Then, as shown in FIG. 6C, the second elastic member 50 isprovided on the protrusions 12, wherein the positioning bumps 121 of theprotrusions 12 may firstly be engaged with the locating holes 511 of thesecond elastic element 50, and it is selectable to apply a glue in orderto facilitate the affixing of the end portions of the second elasticelement 50 to the protrusions 12. After that, the connecting surface 22of the holder 20 and the connecting portion 52 of the second elasticelement 50 are connected to each other (the connection method, forexample, may be engagement or adhering). Furthermore, as shown in FIG.6D, the magnetic elements M are mounted in the recesses 31 of the casing30, and the glue are applied to the corner areas N formed between thesidewall 30R and the groove 32G on the inner surface 32. Finally, asshown in FIG. 6E, the casing 30 is disposed around the base 10. Theinner surface 32 of the casing 30 at least partially overlaps theconnecting surface 22 of the holder 20 from the direction of the centralaxis O, wherein the glue applied to the corner areas N flowscorrespondingly to each of the side surfaces 12R of the protrusions 12of the base 10. As result, the assembly of the lens driving module 1 iscompleted. In one embodiment, the step of disposing the magneticelements M and applying the glue to the casing 30 (FIG. 6C) may becarried out before or after the step of assembling the holder 20 to thefirst elastic element 40 (FIG. 6A).

According to the contents of the embodiment (FIGS. 6A to 6E), thepresent invention provides a method of assembling the lens drivingmodule 1, which mainly includes the steps shown in FIG. 7. The stepsinclude: disposing the holder 20 on the first elastic element 40 (901);assembling the holder 20 and the first elastic element 40 to the base 10(902), in particular, the first elastic element 40 connecting to themain body 11 of the base 10; assembling the second elastic element 50 tothe protrusions 12 of the base 10 (903), wherein locating holes 511 ofthe second elastic element 50 are correspondingly assembled to thepositioning bumps 121 of the protrusions 12; applying a glue to thecorner areas N of the inner surface 32 of the casing 30 (904); anddisposing the casing 30 around the base 10 (905), so that the glue flowsfrom the corner areas N of the inner surface 32 to the side surfaces 12Rof the protrusions 12, and the glue flows in the gaps G between eachside surface 12R and the sidewall 30R, thereby securely affixing thecasing 30 to the base 10. It should be understood that step 904 ofapplying the glue to the inner surface 32 of the casing 30 may beperformed before, between, or after steps 901˜903. A step of assemblingthe coils C to the holder 20 and the magnetic elements M to the casing30 may be performed before step 905.

In the present invention, the second elastic element 50 is connected tothe protrusions 12 of the base 10 and the holder 20 (the step 903)before the casing 30 is disposed around the base 10 (the step 905), sothat there is no need to leave additional space of the opening 301 ofthe casing 30 for the tool to apply the glue to connect the secondelastic element 50 with the holder 20. Thus, the opening 301 can besmaller to avoid or reduce the amount of external dust or particlesentering the lens driving module 1.

Embodiment 2

FIGS. 8A and 8B are schematic diagrams of a lens driving module 2according to another embodiment of the present invention. The maindifference between the lens driving module 2 and the aforementioned lensdriving module 1 (FIG. 1) is that the lens driving module 2 furthercomprises a sensing assembly Q disposed in the casing 30 a, and thecasing 30 a and the aforementioned casing 30 have structuraldifferences. Other components are the same or substantially the same oronly a slight difference in appearance, they will not repeat them here.

The casing 30 a has a plastic material. The sensing element Q isdisposed in the casing 30 a (an receiving space defined by the casing 30a and the base 10) and includes a circuit board F and a pair ofalignment components P (including a first alignment element P1 and asecond alignment element P2 matched to each other, which arerespectively disposed on the casing 30 a and the holder 20). The firstalignment element P1 may be one of a permanent magnet and a Hall effectsensor, and the second alignment element P2 being the other of the two.It is possible for the Hall effect sensor to detect the position of thepermanent magnet by detecting the change of the magnetic field of thepermanent magnet, so as to detect the displacement of the holder 20 andthe optical lens provided therein relative to the base 10 due tovibration. In another embodiment, other types of sensingelements/assembly, such as a Magneto-resistive Sensor (MRS) or anoptical sensor, may also be used to sense the positional relationshipbetween the holder 20 and the base 10. In this embodiment, the circuitboard F and the first alignment member P1 of the sensing assembly Q aredisposed on the casing 30 a, and the second alignment member P2 of thesensing assembly Q is disposed on the holder 20.

It should be noted that the casing 30 a of the present embodiment has aplastic material, the circuit board F and the first alignment member P1(FIG. 8C) are disposed inside the sub-sidewall 30R1 of the sidewall 30Rof the casing 30 a, and one or more wires (not shown) may be formed onthe sidewall 30R of the casing 30 a in a manner of insert molding or 3Dmolded interconnect device (3D MID) technology to connect the circuitboard F, to allow an external power source or other electroniccomponents electrically connected to. Since the wire(s) is/are formed onthe casing 30 a in the manner of insert molding or 3D MID technology,not only can the number of components of the lens driving module 2 bereduced but also the volume of the whole lens driving module 2 can begreatly reduced, and also simplifying and saving assembly costs. Inaddition, when the casing 30 a of the present embodiment is assembled onthe base 10, a slit H1 (corresponding to the receiving recess H2described below) is formed between the casing 30 a and the base 10. Asshown in FIG. 8B, the circuit board F of the sensing assembly Q can beinserted from the slit H1 to be connected to the casing 30 a so that itcan be easily assembled/disassembled by passing through the slit H1.

FIG. 8C shows a more detailed configuration of the casing 30 a and thesensing assembly Q. The casing 30 a further has a holding portion 33 (orholding/clamping wall) disposed substantially perpendicular to the innersurface 32 and parallel to a sub-sidewall 30R1 of the sidewall 30R. Thefirst alignment element P1 is disposed on the holding portion 33. Thesub-sidewall 30R1 of the holding portion 33 and the sidewall 30R definesa receiving recess H2 configured to receive the circuit board F, whereinthe cross section of the receiving recess H2 forms a U-shaped structure(FIG. 8D). Therefore, the circuit board F can be easily inserted fromthe slit H1 (FIG. 8B) to be assembled to the casing 30 a (for example,being a manner of engaging) and also easily disassembled (pulling outfrom the receiving recess H2).

Therefore, by the casing 30 a supporting the sensing assembly Q, themodule in this embodiment can reduce to set a frame for supportingsensing assembly Q, greatly reduce the overall number of components, andin addition to achieving miniaturization for the purpose of simplifyingthe assembly process of the whole module by configuring theaforementioned design of the receiving recess H2.

In another embodiment, the circuit board F and the wires may both beformed on the sidewall of the casing 30 a in a manner of insert moldingor 3D MID technology, to further simplify and save the assembly cost.

In another embodiment, the lens driving module 2′ has a casing 30 b, asshown in FIG. 9. The main difference between the casing 30 b and thecasing 30 a is that the casing 30 b defines a main body 30 b 1 and afirst sub-sidewall 30 b 2 which is separable from the main body 30 b 1(the first sub-sidewall 30 b 2 is detachably connected to the main body30 b 1 and both they have a plastic material), and the sensing assemblyQ (such as the circuit board F and the first alignment element P1thereof) disposed on the first sub-sidewall 30 b 2 (e.g., by insertmolding or 3D MID technology). The sensing assembly Q can be easilyassembled/disassembled by assembling/pulling the first sub-sidewallto/out from the first sub-sidewall 30 b 2.

Embodiment 3

FIG. 10 is a schematic diagram of a lens driving module 3 according toanother embodiment of the present invention. As shown in FIG. 10, thelens driving module 3 is a module capable of sustaining and driving aplurality of (for example, two) optical lenses, comprising a casing 30c, a first holder 25 and a second holder 27, two frames 60, two firstelastic elements 40, two second elastic elements 50, an electromagnetdriving assembly (including four magnetic elements M respectivelycorresponding to the first and second carriers 25 and 27, twosurrounding coils (not shown) being disposed around the first and secondholders 25 and 27 respectively, and two plate-shaped coils CMcorresponding to the first and second holders 25 and 27), a plurality ofelastic members E (eight, for example), two bases 10 (capable ofcarrying image sensors) and two circuit boards F.

In the first holder 25, the first holder 25 can sustain a first opticallens, and one surrounding coil is disposed around the first holder 25and corresponds to four magnetic elements M disposed on the frame 60.The first holder 25 and the frame 60 are movably connected via the firstand second elastic elements 40 and 50, and the corresponding arrangementof the surrounding coil and the magnetic elements M is provided, so thatthe first holder 25 can move relative to the frame 60. In addition, thefour elastic members E connect the second elastic element 50 and thecircuit board F, wherein the circuit board F is sandwiched between thecoil CM and the base 10, and the coil CM corresponds to the fourmagnetic members M such that the first holder 25 and the frame 60 can bemoved relative to the circuit board F, the coil CM and the base 10 foroptical shaking compensation. The second carrier 27, which can sustain asecond optical lens, is also provided with the same or similar elementsaround the periphery of the first holder 25, which will not be describedhere again. By applying a suitable driving signal (such as a drivingcurrent), the magnetic forces generated between the surrounding coilsand the magnetic elements M and between the coils CM and the magneticelements M can independently drive the first and second holders 25 and27 to move along the direction of the optical axes of the first andsecond optical lenses, to tilt relative to the optical axes, or linearmove (relative to the bases 10) in a direction substantiallyperpendicular to the optical axes. Therefore, the optical lenses can bemoved relative to the image sensors disposed on the bases 10 to achieveauto-focusing or optical image stabilization (OIS).

It should be noted that the casing 30 c has a plastic material and isconnected to and disposed on the bases 10 for protecting theaforementioned holders 25 and 27, the frames 60, the electromagneticdriving assembly, the elastic elements 40 and 50, the elastic members Eand the circuit boards F. Furthermore, since the casing 30 c has aplastic material, compared with a lens driving module with an casingthat is generally made of a metal material, which can greatly reduce themagnetic interference to the electronic components (such as an antenna,a Bluetooth device, a magnetic force sensing element, etc.) locatedaround the lens driving module 3. In addition, since the casing 30 c has(or is made of) a plastic material, wires may be provided on thesidewall thereof by insert molding or 3D MID technology and a sensingassembly (such as the sensing assembly Q of the lens driving module 2according to the second embodiment) can be arranged (for example, acircuit board F and the first alignment element P1 are disposed on thecasing 30 c; the second alignment element P2 is disposed on the frame60), to simplify the internal circuit structure.

In another embodiment, as shown in FIG. 11, a lens driving module 3′further comprises a permeability element GM disposed on the casing 30 cand between the first and second holders 25 and 27. In more detail, thepermeability element GM is located between the two magnetic elements Mbetween the first and second holders 25 and 27. Due to the permeabilityelement GM adjacent to the magnetic elements M, the permeability elementGM can not only help the driving module 3′ to dissipate heat but alsoconcentrate the magnetic forces of the magnetic elements M in apredetermined direction to enhance the magnetic forces for moving thefirst and second holders 25 and 27. Moreover, the permeability elementGM can block the electromagnetic interference generated by electroniccomponents in the module 3′, to enhance the performance and longevity ofthe components. In addition, a groove 30 c 4 defined by the protrudingribs 30 c 3 of the casing 30 c can make the permeability element GM morestable and sandwiched (in the optical axis direction) between the casing30 c and the base 10 to reinforce the overall module stability degree.

In one embodiment, an element having a permeability material (e.g., aplate with a permeability material) is embedded on the inner wall of thecasing 30 c which faces the magnetic elements M. In addition toconcentrating the magnetic forces of the magnetic elements M in apredetermined direction to enhance the magnetic forces for moving thefirst and second holders 25 and 27, the mechanical strength of thecasing 30 c can be increased. It should be noted that in someembodiments, if the aforementioned magnetic elements M is moved relativeto the base 10 (i.e., moving-magnetic-element type), the magneticelements M are configured to use a non-magnetic metal material to bemade, to prevent the magnetic interference problems occur by the casing30 c and the magnetic elements M.

In summary, a lens driving module and a method for assembly thereof areprovided. The lens driving module is configured to force an optical lensto move, including a holder, a casing, a base, an electromagneticdriving assembly, a first elastic element, and a second elastic element,wherein the holder is disposed between the first and second elasticelements. The base has a plurality of protrusions. By applying a gluebetween the outer surfaces of the protrusions (which are parallel to thecentral axis of the optical lens) and the sidewall of the casing, thecasing can be firmly assembled to the base. Furthermore, skewed assemblyof the lens driving module caused by tolerances of components may beavoided or reduced due to the side surfaces of the protrusions adheringto the sidewall of the casing. Moreover, before disposing the casingaround the base, the second elastic element is connected to theprotrusions and the holder, so that there is no need to provideadditional space for applying the glue. Therefore, the opening of thecasing may be smaller to avoid or reduce the amount of dust or particlesentering the lens driving module.

Furthermore, the casing of the lens driving module, according to anembodiment of the present invention, has a plastic material and can beused to sustain the sensing assembly which can be formed on the casingby insert molding or 3D MID technology. Thus, it is possible to reducethe number of parts of the lens driving module by saving to setadditional wires, so that the overall volume of the driving module isminiaturization and the assembly cost and process can be reduced.Moreover, compared to the casing with a metal of the electromagneticdrive module, it is possible to reduce the magnetic interferenceproblem.

Use of ordinal terms such as “first”, “second”, “third”, etc., in theclaims to modify a claim element does not by itself connote anypriority, precedence, or order of one claim element over another or thetemporal order in which acts of a method are performed, but are usedmerely as labels to distinguish one claim element having a certain namefrom another element having the same name (but for use of the ordinalterm) to distinguish the claim elements.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the invention. It isintended that the standard and examples be considered as exemplary only,with a true scope of the disclosed embodiments being indicated by thefollowing claims and their equivalents.

What is claimed is:
 1. An optical element driving module, comprising: acasing; a base, comprising at least one protrusion extending toward thecasing, and the protrusion has a side surface, wherein the casing isfixed on the base; a holder for holding an optical element having anoptical axis; a driving assembly for moving the holder relative to thecasing and the base; and a plurality of gluing elements disposed betweenthe side surface and the casing, wherein the side surface is parallel tothe optical axis.
 2. The optical element driving module as claimed inclaim 1, wherein the casing does not move relative to the base.
 3. Theoptical element driving module as claimed in claim 1, wherein the casingcomprises a sidewall extending along the optical axis, and the drivingassembly fully overlaps the sidewall when viewed along a direction thatis perpendicular to the optical axis.
 4. The optical element drivingmodule as claimed in claim 3, wherein the driving assembly comprises adriving magnet having an inner surface facing the holder and an outersurface facing the sidewall, and the area of the inner surface isdifferent from the area of the outer surface when viewed along thedirection that is perpendicular to the optical axis.
 5. The opticalelement driving module as claimed in claim 4, wherein the outer surfaceand the inner surface face opposite directions.
 6. The optical elementdriving module as claimed in claim 3, wherein the gluing elements aredisposed between the sidewall and the side surface.
 7. The opticalelement driving module as claimed in claim 1, wherein the casingcomprises plastic.
 8. The optical element driving module as claimed inclaim 1, wherein a distance between the driving assembly and the opticalaxis is greater than a distance between the casing and the optical axis.9. The optical element driving module as claimed in claim 1, wherein thedriving assembly comprises a coil disposed on the holder and surroundsan axis that is perpendicular to the optical axis.
 10. The opticalelement driving module as claimed in claim 1, wherein the drivingassembly is enclosed by the casing and the base in a direction parallelto the optical axis.
 11. An optical element driving module, comprising:a casing; a base comprising at least one protrusion extending toward thecasing, and the protrusion has a side surface, wherein the casing isfixed on the base, a first holder for holding a first optical elementhaving an first optical axis; a second holder for holding a secondoptical element having a second optical axis; a driving assemblyconfigured to force the first and second holders to move relative to thebase; and a plurality of gluing elements disposed between the sidesurface and the casing, wherein the side surface is parallel to thefirst optical axis.
 12. The optical element driving module as claimed inclaim 11, wherein the casing does not move relative to the base.
 13. Theoptical element driving module as claimed in claim 11, wherein thecasing comprises a sidewall extending along the first optical axis, andthe driving assembly fully overlaps the sidewall when viewed along adirection that is perpendicular to the first optical axis.
 14. Theoptical element driving module as claimed in claim 13, wherein thedriving assembly comprises a driving magnet having an inner surfacefacing the first holder and an outer surface facing the sidewall, andthe area of the inner surface is different from the area of the outersurface when viewed along the direction that is perpendicular to thefirst optical axis.
 15. The optical element driving module as claimed inclaim 14, wherein the outer surface and the inner surface face oppositedirections.
 16. The optical element driving module as claimed in claim13, wherein the gluing elements are disposed between the sidewall andthe side surface.
 17. The optical element driving module as claimed inclaim 11, wherein the casing comprises plastic.
 18. The optical elementdriving module as claimed in claim 11, further comprising a permeabilityelement disposed between the first holder and the second holder.
 19. Theoptical element driving module as claimed in claim 18, wherein thecasing has a groove, and the permeability element is disposed in thegroove.
 20. The optical element driving module as claimed in claim 18,wherein a length of the permeability element is greater than a width ofthe first holder in a direction that is perpendicular to the firstoptical axis.